Localities in which Pellagra is Prevalent. 19 



and few- veined, the stronger veins being close-placed near 

 the anterior margin. 



Alcoholic specimens of the fly received from Dr. M. 

 Francis of College Station, Texas, many years ago, and thus 

 probably altered in color, measure 3.3 mm. (0.13 inch) in 

 length, the relatively large and broad wings measuring a 

 little more, 3.6 mm. (0.14 inch). The head is somewhat pro- 

 duced in advance of the eyes, the palpi rather long and 

 slender, curving downward and posteriorly. Puncturing 

 mouth-parts rather short but sharp and strong, not in evi- 

 dence, except by dissection and microscopic examination. 

 Antenn£e about as long as head, rather thick, of numerous 

 divisions, these crowded, and mostly placed a little obliquely. 

 Thorax very thick, and strongly convex dorsally to accom- 

 modate the powerful muscles of flight. Legs of moderate 

 length, the posterior largest. Abdomen broadly attached to 

 the thorax, oval and tapering to a point behind. 



In his original account of the species the late C. V. 

 Riley describes the sexes somewhat as follows : 



Ma^e. — Eyes meeting and with two sets of facets. 

 Mouth-parts soft. Head black. Antennae black, with some 

 red. Maxillary palpi black. Thorax black above. Abdomen 

 black, with grayish white posterior margins to segments. 



Female. — Eyes not meeting. Head gray slate, with 

 short yellow hairs. Eyes bjack, with coppery or brassy 

 reflections. Antennae black with whitish pubescence. 

 Thorax grayish slate and generally distinctly marked with 

 two medio-dorsal and two subdorsal longitudinal black 

 bands. Under side of thorax, grayish slate. Abdomen 

 with a broad gray longitudinal band from near the base of 

 the second segment, where it is broadest. 



This fly is distributed throughout much of North 

 America, although often denominated the Southern Buffalo 

 Gnat because of the immense numbers occurring in the 

 southern states. It has been recorded from Alaska, New 

 Hampshire, Indiana, Kentucky, Mississippi and Kansas, and 

 unless several species have been confounded, it is to be 

 found in many of the other states. 



